This invention relates to the art of chute systems, and more particularly to chutes for the collection and disposal of refuse of various kinds, as well as the collection and distribution of materials. Further, this invention relates to a mechanism for opening a chute door.
Chute systems are found in numerous applications, such as for the collection of trash in high rise buildings, the collection of laundry in hotels and hospitals and for the collection of medical or other waste. They may also be found in materials handling applications in industrial facilities. For safety or sanitary reasons, chute systems may be fitted with a door closing the opening into the chute during times that material is not being introduced into the chute. This prevents the discharge of particulate matter, odors or other contaminants into the surrounding environment. Also, in the case of a fire or explosion in the chute system, the door provides a barrier which mitigates the effect of the event.
Existing door systems are normally manually operated where the operator opens the door, inserts the material for which the chute is designed, and closes the door. Doors may be fitted with an opening handle and a latch mechanism, such as may be found on a conventional room door, to ensure that the door remains closed when not in use, and may also be fitted with a closing mechanism to urge the door closed. The closing mechanism may be in the form of a spring, with coil spring, leaf spring air spring and pneumatic spring mechanisms being known in the art.
Manually operated doors normally require that the operator use one hand to open the door, and to hold the door open during the period where the material is being introduced into the chute system through the door. If the load is heavy or the operator is handicapped, this may be both awkward and dangerous. In addition, a manually operated door may be opened even if dangerous conditions exist in the chute system, such as a fire, smoke or noxious fumes.
Electrically operated chute doors are known, and they mitigate some of the problems mentioned above, but themselves have disadvantages. Complex mechanical linkage mechanisms are required to effect the door opening and closing, and the electric motor is susceptible to overheating and burn out in the event the door becomes jammed in any position, open, partially open or closed. One means of preventing the continued operation of the motor is to place the motor on a timer, but the motor will operate against the resistance of the jammed door for the entire period that the timer permits. Other means of preventing the continuing operation of the motor include microswitches to sense the open and closed position of the door. It is well known that microswitches present a maintenance and adjustment problem. Another problem associated known electrically actuated doors is that the mechanical linkage mechanism may not permit the door to be opened manually. Attempting to open the door manually may place undesirable stresses on the mechanical linkages and result in a requirement for frequent maintenance.